Treehouse

The Korowai, a Papuan tribe in the southeast of Irian Jaya, live in tree houses, some nearly 40 metres (130 ft) high, as protection against a tribe of neighbouring head-hunters, the Citak.
Materials
Tree houses can be built with a wide range of materials. Wood is commonly used for structural parts and cladding due to its strength, light weight and low cost. Steel is used for brackets, cables and bolts, including specialized tree bolts capable of supporting up to 6,000 pounds (2,700 kg). Builders of tree houses sometimes use recycled materials or parts, such as reclaimed window frames, doors and used lumber. One motivation for this is to promote sustainability by re-using resources. Reclaiming materials can also save money compared with buying new materials and can add a retro or abstract style to the design of the structure. Fabrics can be used to produce non-rigid temporary structures that are more like tree tents than tree houses.